By Bruce Crawford, State Program Leader in Home and Public Horticulture, NJAES, NJNLA
Nearly everyone can enjoy the beauty, fun and ease of container gardening. Containers are a great way to bring the garden to a doorway, balcony, terrace, rooftop or practically any outdoor location. It is especially ideal for those with a limited gardening space and all that is really required is adequate light and accessibility to water!
As you begin to design your container, select plants that will all thrive with similar sunlight, water and nutrient requirements. Choose your location, and match the plants to it. Avoid combining slow growing and vigorous plants in the same container, as the former will quickly overpower the later. Flowering plants are typically the plants of choice, but plants with colorful or architectural foliage are equally as important and often provide a longer period of interest. This is showcased by the spikey Desert Spoon (Dasylirion wheeleri) and succulents as shown above.
The container is equally as important as the plants. Tall plants will need a container with a wide base for stability, while cascading plants will need a tall pot to allow them to drape down the sides. Design themes can be based on using a common color, a specific combination of colors, or simply a repetition of one single plant amongst the containers. All these themes can create a beautiful display when paired with a container whose color compliments that of the plants, as seen in the arrangement above at Wave Hill. Color catches the eye and grabs your attention. Blues, violets and greens soothe and are cool and serene. Reds, oranges and yellows create warmth and brightness. The use of contrasting textures can also create a wonderful design. In the image below from Longwood Gardens, the use of the upright arching foliage of the Bromeliad (Aechmea chantinii ‘Harvey’s Pride’) presents a nice contrast to the slender flowing foliage of the Mexican Feather Grass (Nassella tenuissima).
A container can be designed unto itself if it is sufficiently large. However, a more creative design often results when several pots are laid out together with a cohesive planting design that bridges all the containers, as pictured below at Longwood Gardens. Consider at least three pots of different heights and diameters to provide an attractive layered appearance. Just as with a garden, repetition of plants among the containers is essential for a unified and relaxing appearance. Obviously, the layout of plants and pots will also depend upon the angle from which the pots will be viewed or if they are to be viewed from all directions.
The same concept of repetition is also true for window boxes. It is best for all the boxes to sport the same combination of plants, although the arrangement can vary between boxes. For instance, all pink begonias with cascading ivy or trailing Torenia would create a very simple yet pleasing effect when repeated throughout all the windows.
A common and very successful container recipe is called “thrillers, fillers and spillers”. The thriller serves as the focal point for the container; the spiller are plants that trail over and soften the edges, while also serving to lead your eye down to lower containers; the filler forms the body of the container, often highlighting the thriller. If you are creating a composition of several containers, use one or possibly two thriller plants among all the containers. Just as in a home landscape, too many feature plants makes the composition nervous. Typically, the thriller would go into the largest of the containers and various fillers and spillers would be repeated throughout the remaining vessels. However, gardening is playful and there is no law saying you cannot mix it up and place the thriller into a broad, low container! Also, resist the urge to place the thriller in the center of the container and to ring it with plants. By placing it off-center, there is more room at the front for fillers and spillers and the design does not magnify the radial symmetry of the container.
If you are just starting out or are a seasoned gardener, container gardening is an easy, adventurous and transportable way to indulge your green thumb. The only limit is your imagination.